How to close active connections or create connection timeouts

Good day,Please i need help in solving active connection problems in my office, we have roughly 22 people connected to one database. But after a while, their applications begin to drag due to in and out communication with the server. When i check the active connections on the sql server, some times i see 157 active connections, please how to i set a timeout or connection interval close, so as reduce the heavy load being put on the server. Or how can i automatically close connections when they get higher than 50 connections.This settings should be sql server 2008 relatedThanksTim